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The mechanical characteristics of soft tissues in compression have traditionally been obtained via unconfined compressions. In such tests, frictionless specimen/platen contact in unconfined compression tests has usually been assumed in determining material properties of soft tissues via an analytical solution. Armstrong et al. (1984) and Brown and Singerman (1986) observed that their peak reaction forces in the unconfined stress-relaxation experiments of articular cartilage exceeded the corresponding maximum values predicted analytically. These authors suggested that this discrepancy might have resulted from the friction between the specimens and the platens. Spilker et al. (1990) analyzed the effects of the platen-specimen friction on the mechanical response of cartilage in unconfined compression using a finite element (FE) method. In their study, only two extreme cases in the unconfined compression were analyzed; the specimen either adhered to or was in frictionless contact with the end-platens. In addition, the cartilage was assumed to be linearly biphasic, and an infinitesimal deformation assumption was applied in their analysis. The goal of the present study was to analyze the effect of the specimen-platen friction on the mechanical characteristics of soft tissues in unconfined compression tests via a FE model.